It is the objective of this research project to measure several parameters of corrosion kinetics for dental amalgam made from five representative spherical, lathe-cut and dispersion-type alloys, in an attempt to establish the relationship between corrosion parameters and clinical behavior for these alloys. Amalgam made from the alloys chosen have been shown to exhibit considerable variation in terms of static and dynamic creep, "edge strength," and retention of luster vs. apparent corrosion and marginal breakdown in the mouth. Current potential relationships of the alloys in electrolytes will be obtained to determine corrosion rates and corrosion kinetics. Current and potential sweeps and pulses will be applied to help elucidate rate determining steps. The rotating disc electrode apparatus and the split ring-disc method, respectively, will be used to remove diffusion as a variable and to isolate transient intermediate species during corrosion. Corrosion products in environmental liquids will be determined by atomic absorption spectrometry, and morphological examinations and elemental analysis over small intervals will be studied by SEM and microprobe. Clinical evaluation will be based upon well defined criteria employed by trained clinical examiners in two different institutions thereby providing an opportunity to assess the validity of the evaluation system and to compare it with data obtained by stereo-photogrammetry.